The present invention relates to a transmission device of the reducer type for a self-propelled wheeled machine such as a lawnmower, this device, driven by a belt from a drive shaft, comprising a housing containing a reducing and clutching mechanism between an input shaft and at least one output shaft driving the propelling wheels of the machine, this housing being mounted floating relative to the chassis of the machine, as well as a machine provided with such a transmission device.
The floating mounting of the transmission housing in self-propelled wheeled machines such as lawnmowers, presents a certain number of advantages, particularly as to the time required for mounting and the reliability of the belt tension independently of the manufacturer of the machine. However, the solutions used up to now remain complicated because they require providing pieces adapted to be fixed to the housing. However, the great vibrations generated during operation of the device can lead to untimely disassembly of the pieces or breaking of certain pieces subject to bending or torsion.
An object of the present invention is to provide a transmission device of a new type, whose design permits obtaining a monolithic anti-bending and anti-torsion assembly adapted to operate even in an environment in which it is subjected to great vibration.
To this end, the invention has for its object a transmission device of the reducer type for a self-propelled wheeled machine such as a lawnmower, this device, driven by a belt from a drive shaft, comprising a housing containing a mechanism for reducing and clutching between an input shaft and at least one output shaft driving the propelling wheels of the machine, this housing being mounted floating relative to the chassis of the machine, characterized in that the housing is constituted of half casings assembleable on a joint plane, one of these half casings comprising, formed by molding, a tongue loaded by a spring so as to exert on the housing a swinging couple of the housing about the output shaft to maintain a continuous tension in the belt, this tongue moreover comprising, adjacent its end, an abutment immobilizing a sheath of a control cable acting on a control lever for clutching of the device.
Thanks to the monobloc design of the tongue and of the half casing, the molded tongue forming with the half casing of the housing a monolithic assembly, such a transmission device can operate in an environment subjected to large vibrations without leading to any disassembly between the tongue and the casing. This results in increased reliability of the transmission device.
The invention also has for its object a self-propelled wheeled machine such as a lawnmower, this machine comprising a transmission device of the reduction type driven by a belt from a drive shaft, this device comprising a housing containing a mechanism for reduction and clutching between an input shaft and at least one output shaft for driving the propelling wheels of the machine, this housing being mounted floating relative to the chassis of the machine, characterized in that the transmission device is of the above type.